Method and apparatus for solvent recovery



NOV. 4 192 1. 1,513,928

G. OENSLAGER ET AL METHOD AND APPARATUS FOR SOLVENT RECOVERY Filed Avril 26. 1920 2 Shee ts-Sheet 1 &

imummnnn ww Nov. 4-, i924 1,513,928

G. OENSLAGER ET AL.

METHOD AND ARPARATUS FOR SOLVENT RECOVERY Filed Avril 26 1920 2 Sheets-Sheet 3 m U n 1:! U E1 Z3 flu/621107 34 6. flemlagefl Patented Nov. 4, 1924. 4

UNITED STATES 1,513,928 PATENT OFFICE.

GEORGE OENSLAGER--AND JULIAN C. HOWARD, OF AKRON, OHIO, ASSIGNORS TO THE B. F. GOO'DBIOH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

Application filed Apri126, 1920. Serial No. same.

To all whom it may concern:

Be it known that we, GEORGE OENSLAGER and JULIAN O. HOWARD, citizens of the United States, residing at Akron, in the county of Summit and State of Ohio, have invented a certain new and useful Method and Apparatus for Solvent Recovery, of which the following is a specification.

This invention relates to systems of solvent recovery, which term we employ in a broad sense in connection with the drying of coated or impregnated cord, thread or fabric to drive off the solvent in the coating or impregating material, followed usually by condensation of as much of the solvent as is practicable in order to reclaim it for further use. Our invention is particularlyadapted to the recovery of the vapors of benzol, gasoline or other solvent used in rubber solutions for impregnating and coating cord or fabric, and our object is to provide a simple, safe and compact system or apparatus in which a maximum amount of cord, for example, can

be treated witha minimum occupation of floor space and under such conditions that the work may be readily inspected with the least amount of inconvenience or danger.

Of the accompanying drawings, Fig. 1' is a side elevation, partly broken away, showing a closed-cycle drying and solvent recovery apparatus embodying and adapted to carry out our invention.

Fig. 2 is a front elevation of the drier, partly broken away.

Fig. 3 is a partial rear elevation showing the explosion panels. 5

In the drawings we have shown a vertical drying chamber 10 of relatively great width in one horizontal directidn as compared with its width in the other, and of such height as to occupy two floors of; a building in order that the cord which is treated in said chamber may be sufliciently dried of its contained solvent in one upward and one downward passage through the chamber.

The chamber could be even higher and the drying accomplished in one straight passage of the cord, preferably in an upward direction, but we consider it an advantage to have the cord enter and leave the drier substantially at the same level in order to facilitate attendance. Within the chamber is a single tier of pipe coils 11, through which a heating medium such as steam is circulated, the admission being through a pipe 12 'at the upper end of the tier and the discharge through a pipe 13 at its lower end. The particular character, arrangement and number of the heating devices is subject to variation. The drying chamber 10 is provided at its lower end in the front wall thereof with a series of openings 14 substantially co-extensive with its greatest width, for inspection of andaccess to the cords at the point where they emerge from the coating devices, and for the admission of air to the dryin chamber. These openings may be provi ed with doors, although it has been found that one of the advantages of our system consists in the fact that it may be left open at the lower end without substantial danger or discomfort to the operatives, while at its upper end there may be a high concentration of solvent vapor in the heated air within the drying, space. A series of openings 15, provided with hinged doors 16, 1s formed in the same-wall of the casing at its upper end, for inspection of and access to the work at said upper end, but we do not limit ourselves to this as a location, or the sole location, for suchopenings and doors. In the back wall of the casing at its upper end are formed a series of openings 17, provided with panels 18 of a weak construction, such as cloth faced on the inside with asbestos paper, removably held in place by means of bolted frames 19, so that the panels can readily be renewed. In case of 'an explosion these panels are adapted to blow out and relieve the remainder of the caslng walls from rupturing strain. In back of this row of explosion panels is located an upwardly and outwardly slanted deflector plate 20, adapted to divert the flame ofpthe explosion, should one occur, upwardly toward the ceiling and thus afiord protection to objects or people who may be in the vicinity.

The lower wall of the drying chamber is formed in part by the top wall of a box-like cast-metal structure 21 divided by vertical partitions into a series of solution chambers 22, into which, through a trunk pipe 23 and a series of valved branch pipes 24, is pumped under heavy pressure the liquid with which the cords or threads 25 are to be coated, said liquid, for example, being rubber dissolved in a suitable hydro-carbon solvent such as benzol or gasoline. Nozzles 26, 27 are provided in the upper and lower walls of the im regnating compartments, four pairs to eac compartment bein "here shown, through the several pairs of w ich the cords or sets of cords pass vertically upward. The openstantial loss of solvent vapor.

Immediately below the solution box 21 is located a slanted horizontal bar 28, provided with suitable guiding eyelets for turning the cords from a horizontal to a vertical direction to enter the lower nozzles 26, and in the rear of said box are located a series of pulleys 29 for guiding the descending dried cords out of the drier. The cords pass through the drying chamber 10 upwardly on one side and downwardly on the other side of the steam pipes 11, and at their highest point they pass over a set of guide pulleys 30 in the upper part of the chamber, inspection of and access to these guide pulleys and the cords thereon being obtained whennecessary through the apertures 15 by opening the doors 16., Located in the upper end of the d ing chamber, above this set of pulleys, is a' horizontal pipe 31 formed with openings 32 on its lower .side for drawing 0d the vapor-laden air, this pipe being continued through an extension 32 outside of the drier to a rotary pump 33 which delivers the mixture through a pipe 34 to the lower part of a refrigerating chamber 35, having a perforated false bottom 36 on which lumps of ice 37 are supported. As the mixture of air and hydro-carbon vapor comes in contact with the ice, the major portion of the vapor is condensed to liquid and drained along with the water from the ice through a pipev 38 leading from the bottom of the refrigerating chamber to the lower part of a separating chamber 39. In this chamber the water and the liquid hydro-carbon automatically separate by gravity and overflow at a lower and a higher level respectively through pipes 40, 41, the liquid solvent being recovered from the drip of the pipe 41 and used over again. The air laden with a very small percentage of residual vapor is led oil from theupper part of the refrigerating chamber 35 through a pipe 42 and may either discharge into the atmosphere through a branch pipe 43 or may be led back into the lower part of the drying chamber through a pair of branch pipes 44, thus in the latter case establishing a closed circuit for the air. The refrigerator 35 and discharge pipes 43 are preferably located outside of the main building in which the drier and its associated cord-handling devices are located, but are here shown diagrammatically in the immediate vicinity'of the drier for convenience of illustration. r

In the operation of our Improved system,

the cords or threads entering'the chambers 22 in the solution box 21 through the lower.

nozzles 26 become impregnated and coated with the rubber solution forced into said chambers under pressure through the trunk pipe 23 and branch pipes 24, and, passing upwardly across the openings 14 into the heated part of the chamber 10 on one side of the tier of steam pipes 11, over the pulleys 30, and down on the other side of said tier of pipes, they gradually become dried by the evaporation of the solvent and emerge at the lower end of the drying chamber in a tacky condition, ready to be carried through the winders and reeled up on spools or otherwise subjected to further treatment. Benzol or gasoline vapor, being heavier than air, naturally tends to sink, but the heating of the air in the chamber produces a chimney effect,

regulated by suitablyadjusting the speed of the pump 33 to the rate of feed of the cords 25 and the rate of supply of the heating medium to the pipes 11. The ratio of vapor in the mixture may be varied somewhat within fairly wide limitswithout great danger or inconvenience and is, ofcourse, greater in the upper than in the lower portions of the drier, but it is feasible, by suitable manipulation of the aforesaid variables, accompanied by tests of the content of vapor in the mixture at different heights, to maintain a safe ratio throughout a substantial part of the drying chamber. The use of this apparatus permits a great reduction in the amount of floor space occupied, as compared with horizontal driers, it involves less loss of solvent vapor when the drier is opened for inspection, and it provides for the treatment of a large output of cord in a relatively narrow chamber. The drying of traveling coated fabric or other material in a similar manner may be accomplished with obvious modifications in the apparatus, and the term thread or threads used in the claims is intended to be broad enough to cover individual threads or a Web or strip of threads or other fibrous or coherent material which may be susceptible of treatment by means of our invention.

We claim:

1. The herein-described method which comprises continuously coating a traveling material with solution at the lower end of an upright drying chamber, feeding said material upwardly in said chamber, supplying alimited amount of air to the lower part of said chamber, heating the interior of the chamber to evaporate the solvent, and drawing off the vapor-laden air from the upper portion of said chamber at such a rate in relation to the rate of heat supply and the rate of travel of the material that the ratio of Vapor to air throughout a substantial part of the chamber will exceed that at which the mixture is explosive.

2. The herein-described method which comprises coating threads with rubber solution at the lower end of an upright chamber, heating said chamber, supplying air to its lower portion, feeding the threads upwardly therein, and drawing oil the vapor-laden air from the upper end of the chamber at such a rate in relation to the rate of heat supply and the rate of travel of the thread that the ratio of vapor to air throughout a substantial part of the chamber will exceed that at which the mixture is explosive.

3. An apparatus comprising an upright chamber having thread-coating means and an air-inlet in its lower portion, means for leading threads in an upward path of travel in said chamber, means for heating the interior of said chamber, an outlet from the upper end of said chamber for vapor-laden air, and a suction device connected with said outlet.

4. Drying apparatus comprising an upright chamber having thread coating devices and an air inlet in its lower portion, means for leading threads through said devices into said lower portion and out from the drier in said lower portion, means for guiding the threads upwardly in said chamber from their point of entrance and then downwardly to their point of exit, means for heating the interior of said chamber, and means for drawing off vapor-laden air from the upper end of said. chamber.

5. Drying apparatus comprising an u right drying chamber which is relatively wide in one horizontal direction and rela tively narrow in the other, a solution box having cord-discharging nozzles in the lower part of said chamber arranged in a row following the direction of its greatest width along the front side of the chamber, an air inlet and inspection opening in the lower part of said chamber immediately above the solution box, means for leading the threads upwardly from said nozzles in the front part of the chamber and downwardly in its rear part to an exit at the lower end, heating pipes disposed in a vertical tier in said chamber substantially parallel with the planes of travel of the cord, and means for drawing oil the vapor-laden air from the upper end of said chamber.

6. Drying apparatus comprising an upright chamber having an air inlet in the front wall near the lower end thereof and thread coating means at said lower end, means for heating the interior of said chamber, means for guiding the coated threads upwardly and then downwardly in said chamber, means for drawing off the vaporladen air from the upper part of said chamber, and a relatively weak panel in the wall of said chamber adapted to be ruptured in case of an explosion.

7. Drying apparatus comprising a relatively wide and thin upright chamber having thread-coating means at its lower end and an air inlet and inspection opening in its front wall at said lower end, means for leading the coated thread upwardly and then downwardly in said chamber, means for drawing off the vapor-laden air from the upper part of said chamber, a row of openlngs 1n the wall of said chamber covered by relatively weak explosion-relief panels and external outwardly and upwardlyinclined deflecting means adjacent said openings.

In witness whereof we have hereunto set our hands this 17th day of April, 1920.

, GEORGE OENSLAGER.

JULIAN C. HOWARD. 

